Endoscope having auto-insufflation and exsufflation

ABSTRACT

An endoscopic imaging system for examining a patient&#39;s body cavity includes an endoscope having a distal end, a proximal end and a number of lumens therein. One or more distal gas ports are disposed at or adjacent the distal end of the endoscope and one or more proximal gas ports are disposed proximal to the distal gas ports. Insufflation gas is delivered to the distal gas ports and withdrawn from the proximal gas ports or vice versa such that a gas bubble is formed in the body cavity and travels with the distal tip of the endoscope.

FIELD OF THE INVENTION

The present invention relates to an automatic medical insufflationdevice for diagnostic and surgical endoscopy. In particular, it relatesto a system for and method of creating and controlling an observationspace within a human body cavity so as to optimize diagnostic and/orsurgical endoscopy by insufflation.

BACKGROUND OF THE INVENTION

Endoscopes have been used in the medical field for many years to lookwithin a selected region of a patient's body, e.g., the colon. Theendoscope is typically inserted through an orifice or a surgicalincision into a body channel or cavity. Endoscopes are commonly used toperform surgical, therapeutic, diagnostic, or other medical proceduresunder direct visualization. Conventional endoscopes generally containseveral endoscope components, including illuminating means such aslight-emitting diodes or fiber optic light guides connected to aproximal source of light, imaging means such as a miniature video cameraor a fiber optic image guide, and a working channel. Flexible endoscopesincorporate an elongated flexible shaft and an articulating distal tipto facilitate navigation through the internal curvature of a body cavityor channel. Examples of conventional endoscope designs are described inU.S. Pat. No. 4,706,656, No. 4,911,148, and No. 5,704,899.

Typical endoscopes provide a conduit for the delivery of an inert gas toinsufflate the colon to facilitate examination. The colon, whichcollapses upon itself when empty, must be inflated to create a space,thereby creating a clear field of view for visualization. In order toinsufflate the colon, conventional endoscopic systems utilize an aircompressor or other similar gas supply sources. Insufflation creates aspace for visualization and keeps the gas pressure constant within thecolon by controlling the pressure of the gas supply by means of valves,pressure regulators, and other control devices.

In a standard endoscopic procedure, an operator actively monitors andmanually maintains set-point pressure and flow values by checking thedisplays and operating the controls of the insufflation device. Becausemany systems do not provide quantitatively accurate methods ofregulating the delivery of the gas, those systems can allow variationsin the pressure, volume, and flow rate of gas administered during anendoscopic procedure.

In addition, air pressure in the colon is a cause of pain for thepatient, both during the procedure and afterwards, due to distension ofthe bowel if the pressure is not abated. Furthermore, excessinsufflation pressure can potentially stress, or even rupture, the colonduring the colonoscopy or may cause the development of late perforationsif the pressure and volume of the insufflating gas is not accuratelycontrolled and promptly released.

SUMMARY OF THE INVENTION

To address the problems associated with conventional endoscopicinsufflation systems, the present invention decreases patient discomfortdue to insufflation of a body lumen and allows a physician a clear fieldof view of an interior body cavity. The present invention automaticallycontrols insufflation and exsufflation parameters based on differentoperating modes of the system and/or based on body cavitycharacteristics viewed by the endoscope. In one embodiment, the presentinvention is an endoscopic imaging system of the type that includes anelongated shaft having a proximal end and a distal end. The shaftincludes one or more distal gas ports at or adjacent the distal end ofthe shaft and one or more proximal gas ports. The endoscope is removablyconnected to a control unit having an insufflation gas supply and a gasventing system. Insufflation gas is selectively delivered to the distalgas ports and withdrawn from the proximal gas ports or vice versa duringan endoscopic examination so that a gas bubble is formed around thedistal end of the endoscope. The gas bubble travels with the distal tipas the endoscope is inserted into or withdrawn from the lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates a single-use endoscopic imaging system in accordancewith one embodiment of the present invention;

FIG. 2 is a functional block diagram that shows the interrelationship ofthe major components of a single-use endoscopic imaging system shown inFIG. 1;

FIG. 3 illustrates a distal end of a single-use imaging endoscope inaccordance with an embodiment of the present invention;

FIGS. 4A and 4B illustrate an imaging sensor and heat exchangerpositioned at the distal end of the endoscope in accordance with anembodiment of the present invention;

FIG. 5 illustrates a gas bubble created by the present invention thatmoves with the distal tip of an endoscope; and

FIG. 6 is a flow diagram of an exemplary method of insufflation andexsufflation using the single-use imaging endoscope in accordance withthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As indicated above, the present invention is an endoscopic imagingsystem that performs automated insufflation for use with diagnostic andsurgical endoscopy. Although the present invention is described withrespect to its use within the colon, it will be appreciated that theinvention can be used in any body cavity that can be expanded forexamination and/or surgery.

FIG. 1 illustrates the major components of an exemplary single-useendoscopic imaging system 10. The components of the system 10 include adisplay 12, a user input device 16, and a single-use imaging endoscope18, all of which are functionally connected to a control cabinet 14 thatexecutes application software (not shown) residing therein. Display 12is any special-purpose or conventional computer display device, such asa computer monitor, that outputs graphical images and/or text to a user.Single-use imaging endoscope 18 is a single-use flexible tube thatcontains one or more lumens for the purpose of performing endoscopicprocedures and facilitating the insertion and extraction of fluids,gases, and/or medical devices into and out of the body. Single-useendoscope 18 further contains a digital imaging system (not shown)comprised of, in one example, an image sensor such as a CMOS imager,optical lenses such as plastic optics, a light source such as a numberof LEDs, and an articulating tip that enables steering of the endoscopein a desired direction.

Control cabinet 14 is a special-purpose electronic and electromechanicalapparatus that processes and manages all system functions, and includesa network-enabled image-processing CPU, a physical connection to thesingle-use endoscope 18, an optional dock for the user interface 16, andvalves that control the delivery of gas/water to the endoscope and avacuum line that removes the air/gas and debris, etc., from the patient.User input device 16 is a hand-held device, either wired to the controlcabinet 14 or wireless, that accepts inputs from a human operator viastandard push buttons, joysticks, or other activation devices eithersingularly or in combination to control the operation of single-useendoscopic imaging system 10.

Operation of single-use-endoscopic imaging system 10 is as follows: thesystem is initiated and operated upon command by means of user inputdevice 16, causing the application software executed by a processorwithin the control cabinet 14 to activate the appropriate hardware toperform surgical, therapeutic, diagnostic, or other medical proceduresand to deliver insufflation and/or suction to the lumen(s) of single-useendoscope 18. Display 12 provides live endoscopic video images andvisual feedback of control parameters to the physician or operator sothat an examination of the patient can be completed. Upon termination ofthe examination, the endoscope 18 is disconnected from the controlcabinet and disposed of.

FIG. 2 is a functional block diagram of single-use endoscopic imagingsystem 10 that shows the operational interrelationship of the majorhardware and software elements of the system. A complete description ofthe control cabinet 14 and other components is set forth in U.S. patentapplication No. 10/811,781, filed Mar. 29, 2004, and is hereinincorporated by reference. The single-use endoscopic imaging system 10includes the control cabinet 14 that operates to control the orientationand functions of a single-use imaging endoscope 18. The control cabinet14 includes a controller interface 106 that receives commands from theuser input device such as a joystick, that is used by a physician ortheir assistant to control the operation of the single-use imagingendoscope. Commands from the joystick are supplied to a programmableprocessor such as a digital signal processor that controls the overalloperation of the imaging system and a servo control unit 108. Theprocessor and servo control unit 108 control the operation of a pair ofservo motors 110, 112 that in turn drive control cables within thesingle-use endoscope 18. The orientation of the distal tip is controlledin response to directional signals received from the user input deviceas well as feedback signals obtained from sensors that measure theposition and torque of each of the servo motors 110, 112.

In one embodiment of the invention, the processor and servo control unit108 implement a position-to-rate control that varies the speed at whichthe distal tip is moved as a function of the position of the directionalswitch on the user input device. However, other control algorithms suchas position-to-position or position-to-force (i.e., acceleration) couldalso be implemented.

The control cabinet 14 also includes an imaging board 114 that producesimages from the signals that are received from the image sensor at thedistal end of the single-use endoscope 18. The imaging board 114deserializes the digital video signal from the CMOS imager and performsthe necessary algorithms such as demosaicing, gain control and whitebalance to produce a quality color image. The gain control of the systemis implemented by adjusting the intensity of the illumination (currentsupplied to a number of LEDs) and adjusting the RGB gains to the CMOSimager. The imaging board 114 also includes isolation circuitry toprevent a patient from becoming shocked in the event of an electricalfailure on the imaging board 114 or within the control cabinet 14 aswell as circuitry for transmitting control signals to the image sensorand for receiving image signals from the image sensor. In one embodimentof the invention, the imaging board 114 is provided on a standard PCcircuit board to allow individual endoscopes to be tested with apersonal computer and without the need for an additional control cabinet14.

In the embodiment shown in FIG. 2, the single-use endoscope 18 has adistal shaft portion 120 that is connected to a breakout box 122 with aswivel connection 124. In addition, the proximal portion 126 of theshaft is connected to the breakout box 122 with a second swivelconnection 128. The swivel connections 124, 128 allow the distal andproximal ends of the endoscope to rotate with respect to the breakoutbox 122 and without twisting the breakout box 122 in the hands of thephysician or their assistant.

In the embodiment shown, the single-use endoscope 18 is connected to thecontrol cabinet 14 with a connector 130. Within the connector 130 are apair of spools 132, 134 that are engageable with the driveshafts of theservo motors 110, 112. Each spool 132, 134 drives a pair of controlcables in opposite directions. One pair of control cables drives thedistal tip of the endoscope in the up and down direction, while theother pair of control cables drives the distal tip of the endoscope inthe left and right direction.

The connector 130 also includes a manifold 140 that controls the supplyof fluid, air and vacuum to various tubes or lumens within the endoscope18. In addition, the connector 130 includes an electrical connector 142that mates with the corresponding electrical connector on the controlcabinet 102. The connector 142 transfers signals to and from the imagesensor as well as power to the illumination LEDs and allows connectionto a thermal sensor at the distal end of the endoscope. In addition, theconnector 142 carries signals from a remote pressure sensor as will bedescribed below. Water or another liquid is supplied to the endoscopewith a pump 145. The pump 145 is preferably a peristaltic pump thatmoves the water though a flexible tube that extends into the proximalconnector 130. Peristaltic pumps are preferred because the pumpcomponents do not need to come into contact with the water or otherfluids within the endoscope and it allows the wetted component to besingle-use. A water reservoir 150 connected to the pump 145 supplieswater to cool the illumination LEDs as well as to irrigate the patient.The water supplied to cool the LEDs is returned to the reservoir 150 ina closed loop. Waste water or other debris are removed from the patientwith a vacuum line that empties into a collection bottle 160. Control ofthe vacuum to the collection bottle 160 is provided at the manifold 140within the proximal connector 130. A gas source provides insufflation bydelivering an inert gas such as carbon dioxide, nitrogen, air, etc., tothe lumen(s) of single-use endoscope 18 via the manifold 140.

The processor and control unit 108 executes application software,including GUI software application, system control software application,and a network software application that reside on a computer readablemedium such as a hard disc drive, CD-ROM, DVD, etc., or in a solid statememory. GUI software application is well known to those skilled in theart, and provides the physician or operator with live endoscopic videoor still images and, optionally, with visual, audible, or haptic controland feedback on display 12 using user input device 16. System controlsoftware application is the central control program of applicationsoftware that receives input from sensors, such as from a pressuresensor as described below, and from the user input device 16. Systemcontrol software application provides system control for the functionsnecessary to operate single-use endoscope system 10. The networksoftware application operates a network connection to allow theendoscopic imaging system 10 to be connected to a local area networkand/or the Internet.

As set forth in the application Ser. No. 10/811,781, the manifold 140supplies insufflation gas, water and vacuum to one or more lumens ofsingle-use endoscope 18. The manifold is preferably constructed as aseries of passages that are formed between sheets of a thermoplasticmaterial. Water, air, and vacuum are applied to inputs of the manifoldand selectively delivered to outputs that are in turn connected tolumens within the endoscope 18 by pinch valves on the control cabinet 14that open or close the passages in the manifold. The passages arepreferably formed by rf welding the sheets of thermoplastic into thedesired pattern of the passages.

In accordance with FIG. 2, the basic process of insufflation andexsufflation using single-use endoscopic imaging system 10 is asfollows:

During operation, live endoscopic video images are provided on display12 by the GUI software application, which processes information from theimaging board 114, and the single-use endoscope 18. Prior to operation,insufflation is initiated upon operator command by means of the userinput device 16. As a result, system control software applicationactivates the manifold 140 by means of the pinch valves on the controlcabinet 14. Upon advancing single-use endoscope 18, an insufflation gasis channeled through a dedicated lumen 175 of single-use endoscope 18and into the patient. In one embodiment of the invention, as shown inFIG. 3, the gas delivery lumen terminates at directional port 256, thatdirects the insufflation gas and/or water over a lens 270 of the imagingsensor. As the distal tip of single-use endoscope 18 is advanced intothe colon during the endoscopic procedure, further areas of the colonare insufflated, bringing new examination regions into view.

As single-use endoscope 18 is advanced through the colon, the region ofthe previous field of view is simultaneously exsufflated (collapsed), byconnecting the vacuum source to one or more proximal gas ports 190 thatexit on the exterior of the endoscope shaft and are positioned proximalto the distal gas port(s). The proximal gas ports 190 are connectedthrough a dedicated lumen, or through the “free space” within the shaftof single-use endoscope to the proximal end of the endoscope. Tocollapse the gas bubble, the manifold 140 is activated by a pinch valveto apply vacuum through the one or more proximally located gas ports190. By this means, the body cavity is deflated directly behind the tipof single-use endoscope 18, thus forming a traveling insufflation bubblewithin the body cavity.

As shown in FIG. 4A, the distal end of the single-use endoscope 18includes a distal cap 250 having a number of openings on its front face.The openings include an opening to a working channel 252 and an opening254 for a low pressure lavage, whereby a stream of liquid can bedelivered through the endoscope for removing debris or obstructions fromthe patient. A lens wash and insufflation port includes an integratedflush cap 256 that directs water across the lens of an image sensor anddelivers the insufflation gas to expand the lumen in which the endoscopeis inserted. Offset from the longitudinal axis of the endoscope is alens port 258 that is surrounded by a pair of windows or lenses 260 and262 that cover the illumination sources. An optional pressure sensor 245is also disposed on or adjacent the front face of the distal cap 250 todetect pressure within the body cavity of the patient. Signals from thepressure sensor 245 are transmitted back to the processor and servocontrol unit 108 through the electrical connector 142. A suitablepressure sensor 245 is a miniature pressure gauge available fromNational Semiconductor Corporation or Konigsberg Instruments, Inc.

As best shown in FIG. 4A, the imaging assembly also includes a heatexchanger 280. The heat exchanger 280 comprises a semi-circular sectionhaving a concave recess 282 into which a cylindrical lens assembly 270is fitted. The concave recess 282 holds the position of the lensassembly 270 in directions perpendicular to the longitudinal axis ofendoscope, thereby only permitting the lens assembly 270 to move alongthe longitudinal axis of the endoscope. Once the lens assembly ispositioned such that it is focused on an image sensor 290 that issecured to a rear surface of the heat exchanger 280, the lens assemblyis fixed in the heat exchanger with an adhesive. A pair of LEDs 284, 286are bonded to a circuit board that is affixed in the heat exchanger suchthat a channel is formed behind the circuit board for the passage of afluid or gas to cool the LEDs. A circuit board or flex circuit 292containing circuitry to transmit and receive signals to and from thecontrol cabinet is secured behind the image sensor 290 and to the rearsurface of the heat exchanger 280. With the lens assembly 270, the LEDs284, 286, the image sensor 290, and associated circuitry 292 secured inthe heat exchanger 280, the heat exchanger assembly can be fitted withinthe distal cap 250 to complete the imaging assembly.

FIG. 5 illustrates a single-use endoscope 18 that is inserted into abody cavity such as a colon. As the single-use imaging endoscope 18 isadvanced, gas is delivered through the one (or more) distal gasinsufflation ports to inflate a bubble 502 surrounding the distal end ofthe single-use imaging endoscope 18. Gas is withdrawn from the proximalgas exsufflation ports 190 to collapse the colon at an area 504 proximalto the distal end of the endoscope 18. As the endoscope 18 is moveddistally, the bubble moves distally, as indicated by bubble 506 as shownin phantom lines.

When retracting the endoscope during the examination, the operatorenters the appropriate command on user interface 116, whereby the systemelectronics cause the manifold 140 to reverse the functions of theproximal and distal gas ports at the tip of single-use endoscope 18.That is, insufflation gas is supplied to the proximal gas ports 190 andvacuum is applied to the distal insufflation ports or another port suchas the entrance to the working channel (not shown) located at oradjacent the distal tip of single-use endoscope 18.

As indicated above, the distal end of the single-use endoscope 18includes an optional pressure sensor 245 that allows the processor andservo control 108 in the control cabinet 14 to regulate the pressure ofthe insufflation to provide a clear field of view while reducing patientdiscomfort and lessening the likelihood of potential injury.

FIG. 6 is a flow diagram of a method 400 for the process of insufflationand exsufflation using a single-use imaging endoscope 18 in thesingle-use endoscopic imaging system 10 of the present invention. FIGS.1 through 3 are referenced throughout the steps of method 400. Method400 includes the following steps:

Step 410: Activating System

In this step, operation of single-use endoscopic imaging system 10begins. The operator activates insufflation via user interface 16.Method 400 proceeds to step 412.

Step 412: Selecting Mode

In this step, the operator selects an endoscopic operating mode via userinterface 16 based on whether the operator is advancing or retractingsingle-use endoscope 18 within the colon. During operation, if theoperator does not change the operating mode, the system maintains itscurrent operating mode. Method 400 proceeds to step 414.

Step 414: Advancing or Retracting Endoscope

In this step, system control software activates manifold 140, throughthe control of systems electronics. If the operator chose the advancingmode in step 412, manifold 140 connects an insufflation gas source tothe distal gas port and connects a vacuum line to proximal gas ports 190adjacent the distal end of single-use endoscope 18 or vents the proximalgas ports to the atmosphere. If the operator chose the retracting modein step 412, manifold 140 connects insufflation gas source to theproximal gas ports 190 and connects the vacuum line to the distal gasport at the distal end of single-use endoscope 18 or vents the distalgas port to the atmosphere. Method 400 proceeds to step 416.

Step 416: Reading Pressure

In this step, system electronics samples the output of pressure sensor245. Pressure sensor 245 measures the insufflation pressure in thecolon. The resultant pressure data is passed to the system controlsoftware. Method 400 proceeds to step 418.

Step 418: Pressure Greater Than Upper Limit?

In this decision step, system control software compares the insufflationpressure read in step 416 with a predefined maximum limit in the rangeof 0.1 to 0.5 atmospheres 2-4 psig and determines whether the pressureread in step 416 exceeds this limit. If yes, method 400 proceeds to step420; if no, method 400 proceeds to step 422.

Step 420: Reducing Pressure

In this step, system control software commands manifold 140, to stop orreduce the flow of insufflation inert gas to distal end 300 ofsingle-use endoscope 18. Method 400 returns to step 416.

Step 422: Pressure Less Than Lower Limit?

In this decision step, system control software application 222 comparesthe insufflation pressure read in step 416 with a predefined minimumlimit in the range of 2-4 psig, and determines whether the pressure readin step 416 is below this limit. If yes, method 400 proceeds to step424; if no, method 400 proceeds to step 426.

Step 424: Increasing Pressure

In this step, system control software activates manifold 140, to beginor increase the flow of insufflation inert gas to the distal end ofsingle-use endoscope 18. Method 400 returns to step 416.

Step 426. Shut Down System?

In this decision step, system control software determines whetherinsufflation has been deactivated by operator command via user interface16. If yes, method 400 proceeds to step 428; if no, method 400 returnsto step 412.

Step 428: Deactivating System

In this step, system control software commands manifold 140 to close theinert gas source and vacuum line from the distal end of the single-useendoscope 18. Method 400 ends.

While the preferred embodiment of the invention has been illustrated anddescribed, it will be appreciated that various changes can be madetherein without departing from the scope of the invention. For example,control of the insufflation gas delivered to the patient may be based onother sensed signals besides the pressure detected. Maximum gas pressureand/or flow rate of the gas can be selected by the physician by viewingimages on the display screen or by taking into consideration depth ofinsertion of the endoscope, rate of change in gas pressure, age, sex,size of the patient, etc. It is therefore intended that the scope of theinvention be determined from the following claims and equivalentsthereto.

1. An endoscopic imaging system, comprising: a control cabinet,including: a processor that executes programmed instructions to operatethe endoscopic imaging system; a user input device for receiving controlsignals from an operator; an image processor for producing images oftissue viewed by the endoscope; a display for displaying the tissueimages for a user; an insufflation gas supply for delivering aninsufflation gas to a lumen of the endoscope; a gas venting system forremoving the delivered gas from a patient; and an endoscope removablysecured to the control unit, the endoscope including: an elongated bodyhaving a distal end and a proximal end and one or more lumens; one ormore distal gas ports at or adjacent the distal end of the endoscope;one or more proximal gas ports spaced proximally from the one or moredistal gas ports; wherein the processor controls the insufflation gassupply and the gas venting system such that insufflation gas isdelivered to the distal gas ports and withdrawn from the proximal gasports or vice versa to create a gas bubble that moves with the distaltip of the endoscope as the endoscope is moved to a body lumen.
 2. Theendoscopic imaging system of claim 1, wherein the gas venting systemincludes a vacuum source to draw insufflation gas from a lumen of theendoscope.
 3. The endoscopic imaging system of claim 1, wherein the gasventing system is a valve that is selectively opened to allowinsufflation gas to be expelled from a lumen of the endoscope.
 4. Anendoscope for insertion into a body cavity of a patient, comprising: anelongate body having a distal end and a proximal end, and a number oflumens therein; one or more distal gas ports disposed at or adjacent thedistal end of the endoscope; one or more proximal gas ports disposedproximal to the distal gas ports and coupled to a source of vacuum; amanifold that selectively applies an insufflation gas to the distal gasports as vacuum is applied to the one or more proximal gas ports suchthat an insufflation gas is simultaneously delivered to the distal gasports and withdrawn from the proximal gas ports to create a gas bubblein the body cavity of the patient that moves with the distal end of theendoscope.
 5. The endoscope of claim 4, wherein the one or more distalgas ports are connectable to a source of vacuum and wherein the manifoldselectively applies the insufflation gas to the one or more proximal gasports as vacuum is applied to the one or more distal gas ports.
 6. Amethod of performing an endoscopic examination of a patient's bodycavity, comprising: inserting an endoscope into the patient's bodycavity, wherein the endoscope includes an elongate body having a distalend and a proximal end, one or more distal gas ports disposed at oradjacent the distal end and one or more proximal gas ports disposedproximal to the distal gas ports; and simultaneously delivering aninsufflation gas to the distal gas ports and withdrawing theinsufflation gas from the proximal gas ports as the endoscope isadvanced into the body cavity.
 7. A method of performing an endoscopicexamination of a patient's body cavity, comprising: inserting anendoscope into the patient's body cavity, wherein the endoscope includesan elongate body having a distal end and a proximal end, one or moredistal gas ports disposed at or adjacent the distal end and one or moreproximal gas ports disposed proximal to the distal gas ports; andsimultaneously delivering an insufflation gas to the proximal gas portsand withdrawing the insufflation gas from the distal gas ports as theendoscope is withdrawn from the body cavity.